Rotary spray devices are often used in washing systems for heavy duty use; i.e., for use in removing dirt and other surface contaminants from truck bodies and the like. Such spray devices use rotor assemblies with angled nozzles on the ends of radial arms to produce reaction force tending to spin the rotor assembly while at the same time directing high pressure jets of water toward the surface to be cleaned.
It is generally recognized that it is desirable to limit the speed at which such rotary spray devices operate in order to preserve or extend the life of the bearings used in the rotary coupling to which the nozzle arms are mounted. U.S. Pat. No. 6,193,169 describes a device using a friction brake to achieve this purpose. U.S. Pat. No. 6,209,802 describes another rotary spray using a fluid brake which is built into the spinner housing and includes a pressure regulator comprising a valve and a bias spring.